1. Field of the Invention
The present invention relates to an optical pickup device and, more particularly, to a mechanism for adjusting the position of a light source.
2. Description of the Related Art
In an optical pickup device to be used for picking up Signals from an optical disk or the like, the adjustment between a light source and a light receiving element is necessary for aligning the zero-cross point of focus detecting characteristics and the focal plane of the disk to be irradiated with an optical beam. The following methods are examples of such adjustment:
1. For the adjustment, a lens is moved in the directions of optical axes at the light receiving side;
2. For the adjustment, the light receiving element is moved in the X, Y and Z directions; and
3. For the adjustment, the light source is fixed on a holder and moved back and forth (as disclosed in Japanese Utility Model Kokai No. 40620/1991).
Any of the optical pickup devices listed above has a large number of parts and a complicated structure for the adjustment so that size reduction will be costly. Because of the complicated structure for the adjustment, moreover, the alignment between the zero-cross point for the focus detection and the focal plane of the disk to be illuminated with the optical beam is liable to be disturbed even after it was made. If the lens or the light receiving element is moved at the light receiving side for the adjustment, backlash becomes involved in an adjusting mechanism or the like with the resultant difficulty that the time for making the adjustment is prolonged or that the accuracy is deteriorated.